Air cooled continuous absorption refrigerating unit



Allg. 13, 1940. CAMPBELL 2,210,898

AIR .COOLED CONTINUOUS ABSORPTION REFRIGERATING UNIT Original FiledSept. 20`, 1929 9 Sheets-Sheet 1 //lllnzp\\\\\\\\ l,

Inventor E Bymm A tforney f Aug. 13, 1940. .1.V l.. CAMPBELL AIR COOLEDCONTINUOUS ABSORPTION RFRIGERATING UNIT original Filed sept. zo, 1929 ssheets-sheet 2 Inventor 215, fam/mezz Q By m'- Attorney ug.y 13, 1940. 1L CAMPBELL Y 2.210,898

.AIR 'COOLED CONTINUOUS ABSORPTION REFRIGERATING UNIT v Original FiledSept. .20, 1929 9 Sheets-Sheetv 3 l Inventor Yana/:bell A Bywmz@ Atorney Aug. 13, 1940.

I AIR COOLED CONTINUOUS ABsoRPTIoN REFRIGERATING UNIT Originalr FiledSept. 20, 1929 4f if O 4.7

J. L. CAMPBELL 9 Sheets-Sheet 4 f" ff W z3' ZZ Inventor JLZ. bizz/shellM' A ttomey Aug 13, 1940. J. L. CAMPBELL i 2,210,898

AIR COOLD CONTINUOUS ABSORPTION REFRIGERATING UNIT Original Filed-Sept.20', `1929 9 Sheets-Sheet 5 772' j Inventor ZZ. (yaiZ/QPZ Vf BywwawhHomey I Aug 136 1940' J. L. CAMPBELL. 2,210,898

AIR GOOLED CONTINUOUS ABSORPTION REFRIGERATING UNIT Original Filed Sept.20, 1929 9 Sheets-Sheet 6 g /'V Z n n j i h f u', h l ,ii f ,ff

" l I l 56' Il l| g o' l Il i A 'g ol o Y l j l l i Y. t i i y I Z '46,l 46' .0

In venor llgr l'139 940- J. L. CAMPBELL 2,210,898

AIR cooLED CONTINUOUS ABsoRPTIoN REFRIGERATNG UNIT original Filed sept.2o, 1929 9 Smets-sheet 'r Z M "Z i y In venio' Attorney Aug- 13 1940 J.L. CAMPBELL 2.210,898

' vMR cooLED CONTINUOUS 'ABsoRPTIoN REFRIGERATING UNIT original Filedsept. 2o, 1929 i 9 Smets-sheet a A ttomey All@ 13, 1940- J. l...CAMPBELL 2.210.898

l AIR GOOI-IED CONTINUOUS ABSORPTION REFRIGERATING UNIT OriginalFiledept. 20, 1929 9 Sheets-Sheet- 9 :'mfof' Vean/W5 @ZZ M AttorneyPatented Aug. 13, 1940 UNITED STATE-'s PATENT osi-ics AIR. cooLEDCONTINUOUS ansonrrioN 5 nEFmGEnA'rING UNIT Jackson Lee Campbell,Wichita, Kans., assignor to Sears, Roebuck and Chicago, Ill.,acorporation of New YorkI Application September 20, 1929, Serial No.394,011

'Renewed January 15, 1940 l zo claims.: (ci. ca -119.5)

'I'his invention relates to air-cooled continuacters denotecorresponding parts throughout the ous absorption refrigerating units.several views: I

It has been the experience in the refrlgerating Figure 1 is a frontelevation of a refrigerator art that all refrigerants resistre-absorpton in cabinet provided with a reirigerating unit in" ac- 6 theabsorbing liquids under workingfconditions cordance with the presentinvention. Y f

of artiiicial refrigeration, unless an external y Figure 2`is a top planview of the cabinet of cooling medium such as cool water, is employedFigure 1. to carry away the latent heat of vaporizatlon Figures 3 and 4taken together represent a y which is evolved during. absorption. It istherevertical section in detail, enlarged and having the l0 fore. one ofthe objects of the present'invention back of the cabinet removed. Figure3 being Vlille 10 to eii'ect thorough and complete re-absorption upperPortion thereof.' undy Figure fi being the by the novel construction ofthe absorber, withlower section thereof. y n l out resorting to the useof such a cooling medium. Figure 5 iS .8 Vertical Seiiiiien in detailteken Another object of the invention is to arrange Substantially 0nline 5-5 0f Figulel und 100kthe convolutions of the cooling coil of`the'abing in the direction of the arrows. l5 sorbing unit inconjunction with cooling loops j Figure 6 is a vertical section indetail taken arranged on each convolution to retard the flowSubstantially Online 3-6 01' Figure 1- of a unit of volume of theabsorbing agent; al- 1 Figure 7 is a horizontal Section in detail teken.

lowing ampletime furthe latent heat of vporisubstantially on line 1-1 ofFigure l.

$0 zation of the cooling agent to be dissipated by Figure 8 isahorizental Section in detail teken 20 Vstill air' convectiomtherebycausing the absorb- Substantially 0n line H 0f Figure l. y

ing agent to absorb to its original saturation Figure 9 is a. horizontalsection in detail taken point the cooling agent inltime to begin anotherthrough the lower portion of the rear Well iieycle of operation.lustrating the method of arranging the. lower 8B' A s'till furtherobject of the invention is to tubes ofthe absorber.` Y 25 provide atcritical points in the cycle of opera- Figure l0 is a transverse sectionin detail tion, largenbut compact cooling fins that serve through theSub-generatorto reduce the temperature without the use of Figure 11 is afragmentary perspective View water as a cooling agent. v l illustratingthe arrangement of the tubes of the so Another salient feature of thepresent mabsorber. so

vention is to provide a balance of pressures and 12 is a'verticalsectional View through temperatures within the unit so that there willthe Teeliel'- be a continuous cycle of operation that will dls- Figure13 iS evvertieel Sectional View in detail sipate a maximum amount ofheet, of the strong liquid conducting tube leading from Further objectsof the .invention are to prothe strong liquid receiving member tothe'llquid 35 vide, in a manner. as hereinafter set forth, a heeli'eimnger. v l refrigerating unit of the character referred to,"Figure 14 is diagrammatic View of the re' that is strong compactanddurable. thoroughly frigerating unit in accordance with the presentum invention.

ble in its intended pm very simple in Figure 15 is a. vertical sectionin detail through o its operation extremely simple in its method of 40 lon fthe bsorber. v assembly, adapted for insertion instandard sizedmeg/msi hozontal Section in deta vrefrigerator cabinets andcomparatively inexthrough one of thetubes of the orber. Pen-sivebemnui'eetule and operate v Figure 11 is a'vertical section n detailtaken .With the foregoing and other objects in view, substantially online H-i 1 of Figure 3.

the invention consists -of a novel construction.v Figure i8 is avertical section taken subsi-,en combination and arrangement of parts aswill tially on line IO-It of Figure 3.

be hereinafter mOIe lSieeieally describedy and All parts of the presentunit are/preferably illustrated in the ueeempanying drawings, made oi'steel tubing and containers and all joints wherein is disclosed 'unembodiment 0f the lnareformed by welding sothat asealed continuous 50vention, but it is. to be understood that changes, Aunil; may be formedto carry out the present invariations andvmodincations may be resortedto vention. y without departing from the spirit of the claims Thelre'airigerating unitvin accordance with the hereunto appended.presents-invention is adapted to be installedin a In the drawingswherein like reference charconventional refrigerating cabinet indicatedgen- 55 erally at I having a door 2 hingedly connected as at 3 to theforward edge of one side wall 4. The door is provided with suitablelatching means 3 so as to seal the interior of the cabinet when the dooris closed. The other side wall is indicated at 1, the bottom wall isindicated at 8; and the top wall is indicated at 9. The back wall of thecabinet is indicated at I and supported thereon isA a verticallydisposed hollow shell I I which forms a compartment on the back of thecabinet coextensive with Vthe back wall and is insulated from vtheinterior of the refrigerator cabinet by the rear wall I0. The sidewalls, the top` and bottom walls, the door, and the back wall- Il of thecabinet is provided with suitable insulating material so as to provideresistance to the flow of heat to the interior of the cabinet throughthe walls thereof.

In one corner of the shell there lis provided a square compartment I2through which the gen- `erator D and the sub-generator C extend. The

walls of the compartment I2 are properly insulated from the walls of thegenerator D and the subfgenerator C. The generator D consists 4of avertically disposed, tubular outer shell I3 vand a l spaced tube I4which extends through the outer shell I3 concentric therewith to providea compartment between the tube and the shell for receiving the liquid tobe presently referred to.

The upper end of the outer shell I3 is closed by a cap I5 having anopening in its center which registers with the tube I4 so that excessheat from the tube I4 may be conducted to the atmosphere. At the lowerend the generator D has the compartment between the shell I3 and thetube I4 sealed by a bridgewall I8 that forms also the upper wall of thesub-generator C. The sub-generator C consists of an outer cylindricalshell I1 of slightly greater diameterthan the shell I3 and a concentrictube I8 between which there is provided a compartment to receive thestrong liquor as will be presently described.

rI'he tube I4 communicates at its lower end with the tube I8 whereby theheat is carried upwardly through the generatorand sub-generator.Disposed under the sub-generator C, there is a burner I9 that directsthe name upwardly into the tubes I 8 and I4. The compartment 23 be-`tween the walls ofthe shell I1 and the tube I3 is sealedA at its upperend by the bridgewall I3 and at its lower end by the bottom wall of theshell so that the sub-generator C is a sealedcontainer independent ofthe generator D.

'I'he burner I9 is preferably a gas burner, al` though the system wouldbe adapted for burning acetylene, or any other kind of gas or electriccurrent. A pilot light 2| is disposed on the burner adjacent the tip,and the burner I3 is connected to a thermostatic control member 22 whichis connected with a gas supply conductor pipe 23. The thermostaticcontrol member 22 "is also connected with a thermo-couple 24 that Isdisposed near the evaporator inside of the cabinet. y

A vertically disposed thermosyphon vtube T has its lower end supportedon shell I1 and communicates with the compartment thereon. The up- Derend .of the tube T is welded to the shell I3. adjacent the top thereofand communicates with the compartment betweenthe shell I3 and ,tube I44.of 'the generator D. One end of an arcuate tube E communicates withthe lower end of the compartment between the tube I4 and the shell AtYthe top of the generator D, one end of a' The rectifier K is supportedupon a base 25 that rests upon the top wall 9 of the cabinet.

The rectifier K has spaced radially projecting iins 26 secured to theside walls thereof, the bottoms of which are also secured to the support25. Interiorly of the rectifier K there is piled layers of reticulatedsteel wire 21 that are disposed diametrically of the container (Figure12). One end of the condensing coil L leads from the'top wall of therectifier K and is spirally wound about the outer edges of the fins 26in spaced relation to the walls of the container or rectifier K. Theincline of the coil L is downward so that liquid will flow therethroughunder its own weight.

The lower end of the condensing coil L projects through the top wall 9`of Ithe cabinet and terminates inthe liquid receptacle M formed on theInner wall of the evaporator N. The layers of reticulated fabric 21through the rectifier or container K condense all of the vapor of theabsorbing liquid that may have become entrained in the refrigerant gasflow.

'I'he evaporator N is substantially rectangular in configuration formedwith laterallyprojecting ilns 28 that form continuous rings about theside, top and bottom walls thereof. The evaporator N has an open-ended.compartment 29 for. the reception of ice trays indicated in dotted lineson Figure 1 of the drawings. To the side of the compartment 29, theevaporator N is formed with a closed compartment indicated generally at33 that has a series of spaced, downwardlyv inclining bafe plates 3|having openings 32 at alternate.

ends of each plate, which communicate with the circuitous path, whileany gases may flow upwardly in then compartment.

IBetween the end wall of the compartment 33 and the liquid receivingmember M there is a ilue 33, the upper end of iwhich communicates withthe upper baille plate of the series. A small tubular spout 34 leadsfrom the liquid receiver M, above the terminal of the condensing coilconductor Aand permits the liquid refrigerant to flow upon theA upperbaille plate of the series. The liquid receiver M is a hollow receptacledisposed vertically and preferably formed integral with the inner wallof the evaporator N. The ue 33 is spaced between the one wall of thereceiver M and the inner partition wall that supports the inner ends ofthe baille plates 3|.

Leading from and in communication with' the bottom of the compartment 33 of the evaporator N is a small conductor tube 35 that extendsconcentrically through a. larger tube 33' in spaced relation to thewalls thereof. The larger tube 33 communicates at its inner end with thelower end of the ilue 33 and at its outer end merges with a verticallydisposed annularl bridge wall in the gas heat exchanger O.

'l'.'he gas heatexchanger O consists of a tubular outer shell 31, theone end of which merges with the larger tube 33 leading from theevaporator-N andtheotherend is closed byan end wall spaced verticallydisposed bridge walls 66,66, be-

tween whichA are disposed an annular series oi small tubes 46. Each vofthe bridge walls 66 and 66 are formed with a central openingthatcommunicates withthe small tube 66 at one end, that leads from theevaporator N and the opening on the other bridge wall is incommunication with the tube P. l

The compartment between the-bridge walls' is open and the series oftubes 46 extend through this compartment for the purposes to bepresently described. Between the bridgewall 66 and the end wall 4I thereis a compartment 42, into which extends the upper convolution U oftheabsorber H. In the diagrammatic view shown in Figure 14, the innercompartment between the bidgewalls 36, 36 of the gas heat exchanger'O isreferred to as S, whereas the series of tubes extending be, tween thebridge walls through the compartment S is designated as Q.

The tube P is bent downwardly where it emerges through 4the end wall 4|oi' the heatexchangery and passes across the back wall of the ycabinetas` at 43 and then merges into a depending section 44 that enters thetop of a closed hollow cylindrical container designated at X andreferred to as the strong liquid receiving receptacle. Located at theelbow between sections 46 and 44 is a charging valve 45 through whichthecharge is .introduced into the unit. Into the orice of this chargingvalve is inserted a fuseable plug having a predetermined failure limit,to release the charge should for any reason the pressure within thesystem rise above the normal working limit.

'I'he strong liquid receiving receptacle X is cylindrical in contour andis disposed in a vertical plane along the backwall of the cabinet in thechamber il. Extending up through the bottom wall of the strong liquidreceiving receptacle X is an outlet conductor Y in the form of a pipe 46which projects upwardly into the container for approximately half theheight thereof. The coniined end o1' the pipe 46 is preferablyperforated as shown so as to permit only clean liquid to ilow down theconductor 46. 'I'he liquid from the receiver X iiows by gravity down theconductor 46.

The gooseneck 41 is disposed vertically in the conductor 46 and isprovided with an internal check valve 46a: Figure 13, to prevent anyback pressures at this critical point in the unit. 'I'he conductor 46then enters one .end 4of the liquid heat exchanger F. The heat exchangerF is disposed at an inclination with respect to a horizontal plane andconsists of an outer jacket 46 of insulating material and alongitudinally extending innerchamber or compartment 46 through whichthe conductor 46 extends.

The conductor 46 emerges from'the outer end of the liquid heat exchangerF and enters the compartment 26 of the sub-generator C on substantiallythe saine level as the lower end pf the thermo-syphon tube .-T. 'Iheliquid heat exchanger F is located at the bottom of compartment I i atthe lowest point in the system and communicating with the chamber 46,therein, at the highestpoint thereof, is one end of the arcuatelconductor E that communicates with the generator D. i

Leading from the compartment 46 of the liquid heat exchanger F is a tubeZ that extends upwardly an'd takes a bend 'at right angles into the.upper end of the weak liquor cooling coil G disposed at the top of thechamber H. Leading from the lower convolution of the cooling coil Gthere is a gooseneck 66 of the same height, the top o! coil G to preventor break the syphoning eilect in the unit.

From the gooseneck 66 .a conductor 6| leads downwardly and empties intothe upper end of the upper coil oi' the absorber H where the large tubeemerges from the gas heat exchanger 0.

The cooling coil G is provided with a plurality of ilns 62 which aredisposed between the tuba of the coil i'or the purpose oi'dissipating'heat into the chamber Il and out through the perforated topwall il'thereof, The cooling coil G is continuous in extent and permitsthe now of weak liquor therethrough by gravity. 'I'he coil G is disposedat -the uppermost part of the chamber Il and ab' ve the gas heatexchanger O.

V.'Ihe absorber H consistsy of a continuous coil of large metal tubingU. the convolutions of which are substantially rectangular. The plane ofthe rectangular convolutions is at\ an inclination with respect to ahorizontal plane as will be seen by vreferring to Figure 6. 'Ihe endsections 66 oi' each convolution on the same end incline downwardly,while the endsections 64 opposite thereto incline downwardly in oppositedirections therefrom as will be seen by referring to Figure 4 of thedrawings. One series of individual loops I substantially of U-shapedconiigurations are secured one to each convolution ol' the coil U onthesame end, and. another series ofy loops I are secured in the samemanner to the opposite end of4 each convolution of the coil U.

'I'he opposed loops are staggeredso as to overlap each other in spacedrelation. The convolutions of coil U are of greater cross section but ofless lineal extent than the loops I. The loops I'.

(Figure 11) have .the bights 65 thereof disposed in a horizontal planeand the legs 66, 61 are parallel. Intermediate the ends of the legs 66,61

vthey are bent substantially at right angles as at 66, 69 and the endsof the legs enter the opposite sides 66, 6l of each convolution of thecoil U addacent the inclined ends 62.

Referring to Figures 15 and 16 of the drawings, one side 66 of thevcovnvolutions'U has been selected to illustrate the manner of securingthe one leg 61 thereto and it is to be understood that all of theconnections of the small loops I are connected with the coil U in thesame manner. The end of the leg 61 extendsthrough an opening 6I formedbelow the center oi' the side 66 `and projects therein having its end insubstantial abutment to the opposite wall thereofto form a baille in.the bottomoi the side 66. 'I'he leg 61 projects into the side 66 atright angles to the axis oi' the side. An opening 62 is formed! in thewall oi' the leg 61 in the direction of the axis oi the side 66 abovethe lowest point o'f this side. so that some liquid: will be containedin the large tubes of the coil U.

The end of the other leg 66 is connected in' a like mannerto the lowerside 6I of the samev tarding allows ampie time for the latent heat ofvaporization of the cooling agent to be dissipated by still airconvection thereby causing the absorbing agent to absorb to its originalsaturation point the cooling agent'in time to begin anothercycle.

The cooling coil G is disposed in the upper portion of the compartmentll next to the back wall i0 of the cabinet. The evaporator N is sub- ,y

stantially on the same level as the cooling coil G Vandi is in. theinterior of the cabinet so as to absorb heat therein. The gas heatexchanger O is below the cooling coil G and above the absorber H in thecompartment Il. The liquid heat exchanger F is below the absorber H andat the bottom of the compartnent Il.

In the application of the invention, the units are aembled and testedfor strength under hydraulic pressure of approximately five thousand f ipounds per square inch. It is then immersed in clear water and subjectedto an 'air pressure of one thousand pounds persquare inch to determineif there still remains any infinitely small leaks. When all possibleleaks have been discovered and stopped by welding, it is thanreadyY `forpainting and charging. The charge consists of approximately thirty-tivepercent `(35%) of ammonia and sixty-five (65%) of water at approximatelyiifty degrees. temperature at atmospheric pressure.

hydrogen is forced in under pressure until the f iinal charged pressurein the unit is approximately two hundred and fifty (250) pounds to thesquare inch. When the unit is thus charged, it is ready for operationand the major cycle of circulation is as follows:

The gas burner I9 is lighted and the thermo--v stat for shutting oil thegas inevent the flame should accidentally be extinguished is heldin theopen position for a moment to allow the mercury therein to expand andIthus assume control of the gas valve, then the thermostat is releasedand the entire unit is ready for operation requiring no furtherattention. The ignited gas from the burner i9 slowly heats the strongsolution in subgenerator C causing the ammonia contained in the watersolution to be driven off in the form of a gas, because the absorbingability of water for ammonia decreases as the temperature increases. Dueto the heat being applied, the ammonia is driven oi so rapidly that inpassing up theI small thermo-syphon or percolator pipe T it carries withit globules of the liquid from the subgenerator exactly the same as theaction of a common coffee percolator.

The liquid that passes up the thermo-'syphon tube T is no longer astrong solution, as it has had an appreciable percentage of ammoniadriven off. However, there is still some ammonia contained in theliquid, and this liquid spills from the top of the thermo-syphon -tubeinto the generator D and again comes in contact with the heat from theflue gases passing throughl the generator D where most of the remainingam-` monia is distilled out.

The ammonia in gaseous form passes through the tube-J which inclinesupwardly all the vway to the rectiiier K so that any of theabsorbing yliquid that may have become entrained in the gas now returns downwardlyby gravity into the generator D when it condensesA in the rectiiier K.Theccndensingactionisduetotheexiating pressure and the cooling. eilectof the radiating fins 26 around the rectifier K and also to the bailleplates 21 in the rectilller. Dry ammonia gas is now at the top of therectifier and enterling the top of the ammonia condenser coil L whichcoil winds spirally downwardly through a ,large area of radiating tins,the function of `which is to dissipate the specific `heat of theainmonia gas and in conjunction with the total pressure within thesystem cause the ammonia gas tocondense and form a sealed liquid linejust before reaching the liquid ammonia receiver M in the evaporator N.

The liquid ammonia receiver M lhas a-cubical area sufdcient to hold allthe ammonia that has been distilled out of the absorbing liquid untilthe cooling coil G has filled and ready to begin overflowing into the'absorber H. When the liquid ammonia receiver M is full, the' ammonia isthen ready to begin spilling over into the evaporator N where it iscaused yto evaporate or boil by absorbing heat and thus producerefrigeration in the interior of the cabinet I.

Upon entering the evaporator the liquid am- A, xrionil't comes incontact with hydrogen gas in a comparatively large container where thereis no longer any chance for the liquid to form a seal and due to thepresence of hydrogen gas, the ammonia begins to evaporate in an effortto create for itself its own vapor pressure and this vapor mixes withthe hydrogen gas, which for all practical purposes acts as `an agent tocause theammonia to evaporate. The reason for this actio will beexplained in detail later.

In the evaporator there is now a'mixture of ammonia and hydrogen gaseswhich mixture is heavy as compared to the weight of hydrogen gas alone,due to theV fact that a mixture of ammonia and lhydrogen is specificallyheavier, the greater the percentage of ammonia. This comparatively heavymixture of gases therefore tends to seek the lowest possible level andiiows downward through the evaporator over the series of plates 3|, thefunction of which is to retard the now of and ail'ord as great an areaoi exposed wetted surface as is possible for the liquid ammonia, so thatthe evaporation and diffusion of these two gases may be complete. Thismixtureof ammonia and hydrogen gases then passes out through the innertube S of the gas heat exchanger O through tube P to strong liquidreceiver X, thence upwardly through the absorber In tracing the courseof the weak absorbing liquor, the cycle vis begun in the sub-generatorC. When the absorbing liquid is carried up. through the thermo-syphontube T by the rapid movement of the ammonia gas it is brought back intothe outer shell of the generator D to be further de-nuded of its ammoniacharge, due to the continued action of the hot flue gases passing upthrough the interior tube. A solution of ammonia and water isspecifically lighter than pure water and it follows that the liquid atthe bottom of the generator D would contain thel least amount of ammoniafor -the reason just stated and also for the reason that at this point,that is to say, the bottom of the generator D is nearest to the sourceof heat. Therefore liquid in the bottom of the generator is for alllpractical purDOses pure distilled water.`

Thearcuate tube E allows the hot distilled water to enter the outershell of the liquid heat exchanger F` which is a double shell pipeconstructed on the counter-now principle, and an i exchange of heat iseffected with the strong ammonia and water liquidiiowing throughconductor Y. The comparatively cool liquid coming from the strong liquorreceiver X through the tube Y is preheated before entering the sub-vgenerator C.

The check valve 48x in the gooseneck 41 prevents any, of this heat fromfinding its way through the liquid into the strong .liquor receiver X.The hot distilled water is slightly precooled before entering thecooling coil G through the tube Z. Since this absorbing liquid iscomparatively hot when it enters the coolingcoil at the top, it followsthat the top of the coil will always be the hottest portion, which facttends to create a draft of cool air into the lower unit disposed in thechamber Il.

By the time the distilled Water of the absorbing liquid reaches thebottom of the cooling coil G its temperature has been reducedto withinabout two degrees above` atmosphere. Since the top of the generator D isseveral inches above the highest point of the cooling coil G, some pointin the generator between thetop of the coolingl coil G and the top ofthe thermo-syphon pipe T becomes the hydrostatic head of the absorbingliquid and causes the absorbing liquid to rise in the line Z to the topof the cooling coil G.

At this point in the description, the absorbing liquid has had therefrigerant removed from it,y

and has filled up the cooling coil G and is ready Yto spill over intothe top coil of the absorber H through conductor 5|. On the other hand,the y ammonia has been driven from the absorbing liquid cooled andcondensed in the condensing coil L and the liquid .refrigerant receiverM is' filled ready to spill onto the plate 3| in the evaporator N.

The liquid ammonia flows out of the evaporator N in the gaseous statethrough the gas heat exchanger O through the tube P to the strong liquidreceiver X thence to the lowermost tube of the absorber H where it rstcomes into contact with the absorbing liquid and a portion of thisammonia gas is absorbed by the absorbing liquid flowing down through thecoils of the absorber H and returned to the strong liquid receiver X;

However, a part of this ammonia gas travels `upwardly through the coilsof the absorbervH before it is wholly absorbed by the water, thuscompleting the major cycle.

At this point, the absorbing operation will be described more fully. yThe distilled water flows down through pipe 5l from the cooling coil Gand enters into the upper convolution U of the absorber H. Theconvolutions U of the absorber H arev greater in diameter than theindividual loops I formed at each end ofthe convolutions. Thevammoniaand hydrogen 'gases from the tube P enter the Vlowermost `convolution ofthe absorber H and iiow upwardly through the convolutions U. due to theDreponderating gas head in the tube P and to the fact that as the gasesmove upwardly through the absorber, they`ben come lighter as they comeinto contact with the absorbing liquid until all of the ammonia isab--sorbed by the down flowing weak water solution.

By the time the gas has reached the upper convolution U of the absorberH, the absorbing liquid has absorbed the ammonia gas and consequentlythe-weak liquid has-become a strong mixture of water and ammonia. Theamountof ammonia that will be absorbed by the water at any point isdependent upon the temperature of the waiter. At the time that the waterand ammonia come into contact with each other in the absorber, theammonia gives-oir the heat it has absorbed during its evaporative periodand this heat is dissilpated through the thin walls of the tubes Iassited by the fins 63 disposed about the convo1u tions U and the loopsI. In order to` effect a thermometric gradient or head. so that the heatwill flow rapidly downwardly to the maximum atmospheric temperature inwhich-the apparatus will ever be required to operate, it has lbeen foundthat the best efficiency is produced by having a temperature of aproxi-ymately one hundred and thirty-five ('135) degrees Fahrenheit, in theabsorber, which temperature corresponds to a pressure of two hundred andleighty (280) pounds per square inch in the absorber in order to eifectcomplete re-absorption. A unit of volume of the absorbing liquid in thelarge convolutions U is carried down through the smaller cooling loops Iwhereupon the flow is consequently greatly slowed down due to thediameter of tube I being less than that of the coil Gfrom which theliquid"'comes. This will allow ample time for the absorbing liquidtocool, assisted by thel great area of radiating fins before it againpasses into the presence of ammonia gas ditional Kammonia gas until itstemperature rises .to a point beyond which no more absorption ispossible. I

I'his actionis repeated several times, as can be clearly noted from theaccompanying drawings, before a unit of volume of the absorbing liquidfinally reaches the st rong liquid receiver in its original saturatedcondition, and ready to be again drawn into' the generator for anothercycle.

When the charge of ammonia and water was allowed to flowinto the unit,this' charge occupied only the strong liquid receiver X, the tube 40,the sub-generator and the lower portion of the thermo-syphon pipe T,whereas the hydrogen gas occupied all other void space in the system.However, due to the motivating force of the flame from burner I9,several things have taken place.

The liquid level has been raised from that of the strong vliquidreceiver X- to a point in the Ammonia gas has been distilled off andsubse-y l quently cooled, condensed to a liquid and evaporated in thepresence Aof hydrogen gas. The distilled water has passed through thegenerator down thru the liquid heat exchanger F preheated the strongliquid entering the sub-generator C and passed on up through the tube Zto the cooling coil G whereby the latter is filled.

The hydrogen gas has been forced out of all tubes,'leaving themy assealed liquid lines, and thus preventing the hydrogen from ever againentering them.y While the hydrogen still exerts the total pressure inthe system, the ammonia gas has now assumed the partial pressure overall tubes that have been filled with liquid, due to the fact that thereis nothing in the tube1 J but hot ammonia gas. The hydrogen thereforeexerts a total pressure only upon the liquid surfaces in various partsof the system.

Now the ammonia must be separated from the hydrogen in the absorber sothat the hydrogen can find its way back tothe top of the evaporator N-to start another cycle, and the, ammonia may again be taken from theabsorber to the .liquid receiver to be used again. This is accom- .forhydrogen.

water denudes the hydrogen ofy its ammonia f charge which then leavesthe hydrogen gas extremely light as compared with a mixture of ammoniaand hydrogen gases.

In the latter case, the hydrogen tends to seek the highest possiblelevel which in this case is at the top .of the evaporator, but to reachthe top of the evaporator, it must first pass through the tubes Q in thegas heat exchanger O where the outowing cold mixture of ammonia andhydrogen gases will cool this returning pure hydrogen gas before itagain reaches the evaporator.

As an explanation why the presence of hydrogen gas causes the liquidammonia to evaporate, it wilibe best to review Daltons Law of GaseousPressures, ,which states that every `portion of a mass of gas inclosedin a vessel contributes to the pressure against the walls of the vesselthe same amount that one gas would have exerted by itself, had no other`gas been present. evaporation or boiling point of any liquid isdetermined by the pressure exerted on that liquid by its own vaporpressure and it is not necessarily the conditions of surroundingtemperature and pressure. f e

Therefore, if it be assumed that we 4have a closed container filled withhydrogen gas under any pressure and temperature and that into thiscontainertwe gradually inject liquid ammonia, the container -as yethaving absolutely no ammnil pressure, the liquid ammonia might as wellbe owing into a perfect vacuum. Immediately the ammonia will startevaporating in an effort to create its own vapor pressure under thesegiven conditions, which evaporation continues, until a point ofequilibrium is reached corresponding to the surrounding temperature andpressure.

However, if the bottom of the container is open and a gradual flow ofgas is permitted to pass out at this opening as fast as it flows in atthe top, any amount of ammonia injected into the container willcompletely evaporate since it would never be able to reach its vaporpressure or equilibrium corresponding to the conditions of temperatureand pressure.

By reason of this fact there is a continual circulation of hydrogen gaswhich is carrying away the ammonia vapor as fast as it forms. The aboveconditions have been created in the system under discussion herein.

As stated before, 'the final charged pressure of this system isapproximately two hundred and e fty (250)- pounds to the square inch,which pressure is constant throughout the entire system.. The operatingpressure however, due to a slight rise in temperature within theabsorber, )increases to approximately two hundred and eighty (280)pounds to the square inch.

Under these 'conditions of pressure, the hydroegn remains a gas and theammonia a liquid. The liquid ammonia gradually spills from the receiverM into the evaporator in the presence of hydrogen gas and immediatelystarts evaporating in an effort to create its own vapor pressure, Thisevaporation is accompanied by a fall in `temperature `corresponding tothe reduction of vapor pressure and this evaporation and mixing goeson,l until the ammonia vapor has reached the'partial pressure in themixture of gases which corresponds to the existing Condi- The i tions oftemperature and pressure in the evaporator. f

As the ammonia is thus diffused intothe hydrogen, its partial pressurefalls, but the total pressure in the evaporator remains the same, as inall other parts of the system. As before stated, this mixture of gasessinks downward through the evaporator dueto its higher specific gravitythan pure hydrogen and passes through the gas heat exchanger O totheabsorber where the shower of absorbing liquid denudes the hythe hydrogenthus liberated assumes the total pressure in the upper part of theabsorber and because it is light in weight, will seek the highest pointin the system, which is at the top of the evaporator.

Consequently, there is a continual circulation of gas between the strongliquid receiver X, the

absorber H and gas heat exchanger O and evapl orator N.

The above explanation covers the major cycle of all agents contained inthe system. However, in this major cycle, there are three sub-cycleswhich are set out below.

First, an absorbing liquid cycle or water cycle.

Second, a refrigerating agent cycle, or am'- monia cycle.

tube E to the liquid heat exchanger F, upward through the tube Z to 'thetop convolution of the cooling coil G, then downward through the coil G,up one leg of the goose neck 50, down the tube 5I emptying into theuppermost convolution U of the absorber H.

From the convolution U, the absorbingdiquid flows downward in oneleg ofthe auxiliary loop I and upward in the other leg thereof, then theabsorbing liquid passes transversely along the horizontal convolution Uto the other end thereof,where it is conducted through the auxiliaryloop in the same manner as stated above. The absorbing yliquid continuesthis tortuous course by gravitational force until it reaches the strongliquid receiver X, from which it is drawn into the sub-generator throughthe tube Y in which is disposed a gooseneck 41 containing the checkvalve 48x.

The function of the check valve 481 is to effect a pressure gradient in'the sub-generator sufilcient to overcome the specific weight of thecolumn of liquid in the thermo-syphon tube T so that it will be raisedto the new hydrostatic head in the generator D, thereby assuring apositive directional flow of the liquid thru the system.

When this unit of volume of the absorbing liquid has been thus raisedand discharged into the generator D, the thermo-syphon tube T ismomentarily clear of liquid, which immediatelyv allows the totalpressure of the sysfem to become equalized, then due to the hydr statichead in the liquid receiver X, the check valve Ais caused to openandallow the strong liquid to pass in through the sub-generatorr and risein the thermo-syphon tube T to the level of that of the liquid in thereceiver X. The operation of the drogen gas of its ammonia charge atwhich time asiduos D, then through the inclined tube J to the recytiiier K.` From the rectiiier K through the cool- V ing and condensingcoil L, to the liquid ammonia receiver M, through theevaporator Nthrough the tube S of the gas heat exchanger O and then through the tubeP tothe absorber H from where the flow is through the strong liquidreceiver X and again to the sub-generator through the tube Y.

'I'he hydrogen cycle is from the absorber H through the outer shell, ofthe gas heat exchangerO, to the top of the evaporator, and downwardthrough the evaporator to the gas heat exchanger, through the inner tubeS thereof, back to'the absorber through the tube P.

The operation of the machine is a repetition of these cycles whichoverlap and intermesh and it will operate continuously without attentionso long as the heat is applied to the generator.

As before stated, the unit is designed to withstand an internal pressureof five vthousand pounds per square inch. The unit is fully charged andready for operation before. it leaves ,the factory and from researchavailable, will never require recharging. The seventy-five pound unit isdesigned to operate at maximum efilciency with a heat input ofapproximately fifteen hundred B. t. u.s per hour, which heat isdissipated by both the top ammonia coil L and the absorbing liquid VcoilG.

The corresponding heat extractions from the interior of the cabinet isapproximately equal to that of the melting of slightly over three poundsof ice at thirty-two (32) degrees Fahrenheit per hour, or a B. t. u.extraction of approximately four hundred and fifty (450) per hour, whichheat is dissipated by the radiating fins and surfaces of the absorberdue to its novel construction heretofore pointed out. f

While the invention has been described as operating with water as anabsorbing medium, ammonia as a refrigerant, and hydrogen as an inertnon-condensable gas, it is to be understoodv that the use of other mediais contemplated.

Furthermore, it is to be understood that by describing in detail hereinany particular form, structure, arrangement orpsequence of operation, itis notintended to limit the invention beyond the terms of theseveralclaims or the requirements of the prior art.

y Having thus described'my invention, what I claim is:

i. A refrigerator comprising a generator consisting of a pair of sealedcompartments one above the other, a conductor communicating with the topof the upper compartment and with the lower compartment, a source ofheat under the lower compartment, a mixture of an absorbing liquid and acooling agent in the lower compartment, a condensing chamber, a weakliquor cooling coil, an evaporating compartment having vertically spacedhorizontal plates therein provided with openings in alternate endsthereof, a receptacle formed in the evaporator toreceive they condensedcooling liquid, a spout leading from Vvthe receptacle for-directing thecondensed cool,-

ing liquid on said plates, a gas heat exchanger connected to theevaporator, said evaporator having a flue to conduct-a non-condensablegas from the gas heat exchanger to the evaporator, absorbing coilsconnected with the gas heat exchanger,

a receptacle connected with the lower convolution of the absorber coilsand a liquid heat exchanger connected with said receptacle andthe upperand lower generator compartments.

v2. A refrigerator comprising a pair of'superimposed sealed generatingcompartments, a heat l supply in contact with the lowermost compartment,a condensing receptacle and coil connected in spaced relation to theupper generating compartment, an evaporator having a receptacle thereinconnected with the condenser for receiving the condensed ycooling agent,a gas heat exchanger connected with the evaporator, absorbing coilsconnected with the heat exchanger, a strong liquid receiver connectedwith the lowermost coil of the absorber, a heat exchanger connected withthe strong liquid receiver and to both compartments of the generator.

3. Refrigerating apparatus of the closed absorption type wherein aconstant total pressurev is maintained on the absorbing medium and therefrigerant by a non-condensabl pressure equalizing agent; comprising incombination, a generator, a sub-generator for containing a mixture of.absorbing liquid and a refrigerant, a thermosyphon tube incommunication with both generators for conducting refrigerant vaporsfrom one to the other, a source of heat for the sub-generator tovaporize the refrigerant, a rectifying receptacle. for condensing theabsorbing liquid, a

conductor in communication 'with the rectifier and generator, anevaporator includi g aninternal liquid refrigerant receptacle, lanon-condensable gas passage and apertured spaced'inclined baille plates,an air cooled refrigerant condensing coil in communication with the saidrefrigerant receptacle and the rectifying receptacle,

a gas heat exchanger in communication at one end with the baille platesand the non-condensable gas passage, an air cooled absorbing coil in.communication with the outer end of the gas heat exchanger, 'a pluralityof tubular cooling loops connected at spaced points on said absorbingcoil `whereby fractions offiuid may be" succes sively by-passed out ofthe main body of said municationvwith the saidyother end of the gas '4sfluid in said coil, a strong liquid receiver in comheat exchanger andthe lowermost convolution of the absorbing coil, a liquid heatfexchangerin communication with the generator. a conductor communicating with thestrong liquid receiver and the liquid heat exchangerand an internalvalve responsive to the hydrostatic head gradient in the generatordisposed in the last mentioned conductor.

t. That improvement in refrigerating apparatus of the'closed absorptiontype, wherein a constant total pressure is maintained on the absorbingmedium and refrigerant by a non-condensable pressure equalizing agent;including a generator and sub-generator, a thermo-syphontube incommunication with both generators, an absorbing liquid rectier incommunication with the generator, a strong liquid receiver, an aircooled refrigerantcondensing` coil in communication with the rectifier,and a liquid and gas heat exchanger, comprising in combination, anevaporator having an internal receptacle for a condensed refrigeratingliquid provided with an opening in communication with the refrigerantcondensing coil, alternately apertured spaced inclined baille plates,disposed internally of the evaporator and 1 sibleV pressure equalizinggas; absorbing the cooling agent in absorbing liquid and dissipating thelatent heat of vvaporizationby atmospherically cooling the absorbingagent in a series of progressive steps by subjecting fractions of theabsorbing agent to heat exchange relation with the atmospheric air, andreturning cooled fractions to the main body of the absorbing agent;heating the absorbing liquid to separate the cooling agent and theabsorbing liquid; cooling and condensing the cooling agent byatmospheric air; cooling the heatedabsorbing liquid from which thecooling agent has been separated by means only of atmospheric air; againevaporating the condensed cooling agent by atmospheric heat in'thepresence of the non-condensible pressure equalizing gas, all in closedcontaining means, circulation of gas in saidcircuit taking place solelyby difference in specific weights of gas in different parts of `saidcircuit.

6. A method of refrigerating comprising evaporating a condensablecooling agent from a mixture of' a liquid absorbing agent and thecooling agent, condensing the cooling agent to `a liquid, evaporatingthe cooling agent in the presence of a non-condensable gas and causingthe gaseous.

mixture of the cooling agent and non-condensable gas tocontact with thedenuded absorbing agent, during the period of contact causing thecooling of the absorbing agent in a series of progressive steps bypassing fractions of said absorbingl agent into heat, exchange relationwith the' atmospheric air and returning said fractions which have beenthus cooled to the main body of the absorbing agent, whereby the coolingagent is absorbedand the vnon-condensable gas is liberated to continueanother cycle of operation, the circulation of .gas in said circuittaking place solely by difference in the specific weights of the gasesin different parts of said circuit.

7. A method of refrigeratingcomprising'evaporating by means ofartificial heat' a condensable cooling agent from a mixture of a liquidabsorbing agent and the cooling agent, condensing the cooling agent to aliquid, evaporating the cooling agent in the presence of anon-condensable gas andcausing the gaseous mixture of the cooling lagentand non-condensable gas to contact with the denuded absorbing agent,during the period of contact causing the cooling of the absorbing agentin a series-of progressive steps by passing fractions of said absorbingagent into heat exchange relation with the atmospheric air and returning4said fractions which have been thus cooled to the main body ofA theabsorbing agent,

whereby the cooling agent is absorbed and the non-condensable gas isliberated to continue an other cycle of operation, the circulation ofgas in said circuit taking place solely by difference in the specicweights of the gasesl in dierent parts of said circuit; x

8. A method of refrlgerating comprising evaporating a condensablecooling agent from a mixture of a liquid absorbing agent andthe cooling.absorbing agent, during the period lof contact causing the cooling ofthe absorbing agent in a series of progressive steps by passingfractions of said absorbing agent into heat exchange relation with theatmospheric air and returning said fractions which have been thus cooledto the main body of the absorbing agent, whereby the cooling agent isabsorbed and the non-oondensable gas is liberated to continue anothercycle of operation, the circulation of gas in said circuit taking placesolely by difference in the speciilc weights of the gases in differentparts of said circuit. 4

' 9. A method of refrigerating comprising evaporating a.condensablecooling agent from a mixture of a liquid absorbing agent andthe-cooling agent by an application of extraneous heat, collecting theabsorbing liquid separate from the cooling agent, condensing the coolingagent by means of air, causing the cooling agent to evaporate in thepresence of a non-condensable gas, and causing thegaseous mixture of-the noncondensable gas and cooling agent to contact with the denudedabsorbing agent, during the period of contact causing the cooling of theabsorbing agent in a series of progressive steps by passing fractions ofsaid absorbing agent into heat exchange relation with the atmosphericair and returning said fractions which have been thus cooled to the mainbody of the absorbing agent, whereby the cooling agent is absorbedandthe non-condensable gas is liberated to continue another cycle ofoperation, the circulation of gas in said circuit taking place solely bydifference in the specific weights of the gases in different parts ofsaid circuit.

A10. `In a continuous absorption refrigerator, including alcabinet, arefrigerating compartment in the forward portion of said cabinet, a fluein said cabinet having an outlet at the rear of said refrigeratingcompartment, an evaporator in said refrigerating compartment and anabsorber operatively connected to said evaporator and in operativerelation to air passing through said flue, said absorber having arelatively fiat general shape and comprisinga plurality of elongatedcooling coll portions provided with fins, certain of said elongatedportions being positioned in parallel relative to the path of flow ofcooling air through said ue and connected to one another in series flowfor the passage of refrigerant fluid, inert gas, and absorbent; saidelongated portions having a relatively low slope so as to produce a slowow of absorbent fluid and a relatively great cooling thereof, and theentire absorber assembly having accross sectional shape conforming tosaid' flue to thereby efficiently utilize the cooling air flowingthrough said fiue; means to feed a mixture of -refrigerant and inert gasfrom said evaporator to one end of said absorber and means to feed`absorbent fluid to the other end of said absorber.

refrigerating compartment, an evaporator in said refrigerati'ngcompartment and an absorber oper- 7l produce a slow flow of absorbentiiuid and a rela'-- tively great cooling thereof, and the entireabsorber assembly having a cross sectional shape conforming to said flueto thereby efficiently utilize the cooling air flowing through saidflue; means to feed a mixture of refrigerant and inert gas from saidevaporator to the lower end of said.,

absorber and means to feed absorbent fluid to the upper end of saidabsorber. f 12. In a continuous absorption refrigerator, including acabinet, a refrigerating compartment in the forward portion o f saidcabinet, a ue in said cabinet having an outlet in the upper rear of saidcabinet, and aninlet at the lower portion of said cabinet, an evaporatorin said refrigerating compartment, and an absorber operatively connectedto said evaporator and in operative relation to air passing through saidflue, said absorber having a relatively fiat general shape andcomprising a plurality of elongated cooling coil portions, provided withfins, certain of said elongated portions being laterally positionedr andspaced relative to one another and connected to eachother in series`flow for the rpassage of refrigerant fluid, inert gas, and absorbent;said elongated portions having a ,relatively low slope so as to producea slow flow vof absorbent fluid and a relatively great cooling thereof,and the entire absorber assembly having a cross sectional shapeconforming to said iiue to thereby efciently utilize the coolingair-owing through said flue; means to feed a mixture of refrigerant andinert gas from said evaporator to the lower end of said absorber andmeans to feed absorbent fluidto the upper end-of said absorber.

13.y In a. continuous absorption refrigerator, including a cabinet, arefrigerating compartment in the forward portion of said cabinet, a uein said cabinet having an outlet in the upper rear portion of saidcabinet, and an absorber in operative relation to air passing throughsaid ue, 'said absorber including a plurality of U-shaped portions inseries connection for the `passage of refrigerant fluid, inert gas, andabsorbent therelthrough, one leg of each U being laterally disposedrelative to the other leg, and one of said legs being'at a lower generalelevation than the other so as to receive .absorbent fluid from saidother leg, means to feed a mixture of refrigerant and inert gas fromsaid evaporator to the lower end of said absorber, and means tov feedabsorbent -uid to the upper endof lsaid absorber, the legs of saidU-shaped portions having a relatively low lslope so as to vproduce aslow flow of absorbent flow of air therethrough and constituting a flue.

an absorber having a relatively flat general shape conforming in generalcross section to said ue positioned inthe lowerportion of said secondcompartment, means within said `absorber to retard the ow of absorbentfluid therethrough, and an additional heat-rejecting element in theupper portion of saidcompartment above said absorber.

15. In'a continuous absorption refrigerator including a cabinet, arefrigerating compartment in the forward portion of said cabinet, asecond compartment insulated from said refrigerating n 'compartment insaid cabinet, said second compartment being open at the bottom and topfor 'the ilowy of air therethrough and constituting a flue, an absorberhaving a relatively flat general shape conforming in general crosssection to said flue positioned in the lower portion of said secondvcompartment, and an additional 'heat-rejecting means in said flueadapted to promote 'the flow of cooling air through. said flue. and inheat exchange relation to said absorber. d

16. In a continuous absorption refrigerator, including a cabinet, arefrigerating compartment in the forward portion-of/said cabinet, asecond compartmentinsulated fromsaid refrigerating compartment in saidcabinet, said second compartment being open at the bottom and top forthe flow of air therethrough, and constituting a flue, an absorberhaving a relatively fiat general shape conforming in general crosssection' to said flue ed to promote the iioW of cooling air through saidflue and in heat exchange relation to said absorber.

17. In a continuous absorptibn refrigerator, including a cabinet, arefrigerating compartment in the forward portion of said cabinet,asecond compartment insulatedv from said refrigerating compartment insaid cabinet, said second compartment being open at the bottom and topfor the flow of air therethrough and constituting a flue, an absorberhaving a relatively at general shape conforming in general cross sectionto said flue positioned in the lower portion of said second compartment,means to. feed a mixture of inert gas land refrigerant into saidabsorber,

means to discharge inert gas from said absorber,

and a heat-exchanger for the mixture of inert gas and refrigerant fedinto said absorber and the inert-gas discharged therefrom, said heatexchanger being positioned in said flue above said absorber. l

18. In a continuous absorption -refrigerator, including a cabinet-arefrigerating compartment in the forward -portion of said cabinet, asecond compartment insulated from said refrigerating compartment in saidcabinet, said second compartmenhbeing open at the bottom and top for theow of, air therethrough and constituting a iiue, an 'absorber having arelatively flat general shape positioned in the lower portion of saidsecond compartment, and an absorbent, cooling coil insaid flue abovesaid absorber.

19. In a'continuous absorption refrigerator, in-` cluding a cabinet,l arefrigerating compartment in the forward portion of said cabinet, a fluein said cabinet having an outlet at the rear of said refrigeratingcompartment, an evaporator in said refrigerating compartment and anabsorber operatively connected to said evaporator and in operativerelation to air passing lthrough said flue,

said absorber having a relatively fiat general shape and comprising aplurality of elongated cooling coil portions provided with ns, certainof said elongated portions being positioned in parallel relation to thepath of fiow of cooling air through said ue and connected to one anotherin series flow for the passage of refrigerant fluid, inert gas,'andabsorbent; means in said elongated portions to retard the i'low ofabsorbent uid through said portions and thereby produce pools ofabsorbent iiuid therein; means to feed a mixture of refrigerant andinert gas from said evaporator to one end of `said absorber and means tovfeed absorbent fluid to the other end of said absorber. g

20. In a continuous absorption refrigerator, including a cabinet, arefrigerating compartment in the forward portion of said cabinet, a fluein said cabinet having an outlet at the rear of said refrigeratingcompartment, an :evaporator in said refrigerating compartment and anabsorber open atively connected to said evaporator and in operativerelation to air passing through said iue, said absorber having arelatively flatv general shape and comprising a, plurality of elongatedcooling coil portions provided with tins, certain of said elongatedportions being positioned in parallel relative to the path of flow ofcooling air through said ue and connected to one another in series flowfor the passage of refrigerant uid, inert gas, and absorbent; dammembers within said cooling coil portions extending substantially abovethe .l bottom surface thereof to retard the flow of uid therein; meansto feed a mixture of refrigerant and inert gas from said evaporator .toone end of said absorber and means to feed absorbent uid to the otherend of said absorber.

JACKSON LEE CAMPBELL.

